A multi-chamber washer is generally comprised of several different chambers that are aligned side-by-side. Each chamber within the washer has a specific purpose, such as washing, rinsing or drying. Objects to be washed within a multi-chamber washer are typically conveyed through the washer in an open basket or rack. The basket or rack moves from one chamber to another along a conveyor system that extends through the washer.
To monitor the position of the racks within the washer, it has been known to place identification tags on the racks and provide a scanning device at the entrance to the washer. It is also known to monitor the position of the racks or baskets within the washer by using magnetic switches. In this respect, a magnet would be installed on the rack. This magnet is detected by a sensor disposed within the washer along the conveyor path. Such sensing systems are typically employed with a stopping mechanism within each chamber that stops the racks or baskets at a certain position within each chamber. Accurate positioning of a rack within a chamber is required for a number of reasons. For example, some racks include specialized spray devices that require connection to water sources at predetermined locations within the washer. Thus, a rack must be aligned with such sources, to ensure proper connection thereto.
To facilitate accurate positioning of the racks within the washer, mechanical stops have been provided at predetermined positions within the washer to stop a rack moving along a conveyor at such predetermined positions. Typically, such stops are comprised of a barrier attached to a cylinder. The cylinder is typically oriented perpendicular to the path of the racks to move the barrier into and from a position obstructing the path. In other words, the cylinders are at right angles to the direction of movement of the racks, with the barrier located at the end of the cylinder rod. As such, when the cylinder is in a fully extended position with the barrier intersecting the path of a rack, a force perpendicular to the axis of the cylinder rod is exerted on the cylinder rod when the rack engages the barrier. Such a force tends to cause premature wear of the cylinder as a result of the end of the cylinder rod being pushed out of axial alignment with the cylinder.
Another problem with indexing systems known heretofore is that the magnetic switch systems as described above require a magnet on each rack that is used within the washer. Moreover, the rack or basket must be properly aligned and oriented within the washer to ensure that the magnet on the rack moves past the sensor. In addition to the foregoing, damage to the basket outside of the washer can result in improper or faulty readings when a damaged rack or magnet is used within the washer. Still further, positioning of sensors within the washer unit places the sensor in a damp, wet environment wherein the sensors are more likely to fail.
The present invention overcomes these and other problems and provides an improved indexing system for positioning racks or baskets within a multi-chamber washer.